mtr: use new optional deps support

Signed-off-by: Jack Nagel <jacknagel@gmail.com>
postgresql: use new recommended deps support

Signed-off-by: Jack Nagel <jacknagel@gmail.com>
v8cgi: use new optional deps support

Signed-off-by: Jack Nagel <jacknagel@gmail.com>
gnome-doc-utils: depend on libxml2 'with-python'

Signed-off-by: Jack Nagel <jacknagel@gmail.com>
duplicity: make universal optional

Signed-off-by: Jack Nagel <jacknagel@gmail.com>
jbigkit: make universal optional

Signed-off-by: Jack Nagel <jacknagel@gmail.com>
libffi: make universal optional

Signed-off-by: Jack Nagel <jacknagel@gmail.com>
libgcrypt: make universal optional

Signed-off-by: Jack Nagel <jacknagel@gmail.com>
libgpg-error: make universal optional

Signed-off-by: Jack Nagel <jacknagel@gmail.com>
librsync: make universal optional

Signed-off-by: Jack Nagel <jacknagel@gmail.com>
readline: make universal optional

Signed-off-by: Jack Nagel <jacknagel@gmail.com>